In manufacturing semiconductor devices, a target substrate, such as a semiconductor wafer, is subjected to various processes, such as a film-formation process and etching process. In order to perform processes of this kind, vacuum processing systems are employed. A vacuum processing system includes a plurality of vacuum containers that define vacuum chambers. These vacuum chambers are exemplified by a process chamber for accommodating a target substrate and performing a predetermined process thereon; a load-lock chamber for adjusting pressure between atmospheric pressure and vacuum; and a transfer chamber having a transfer device disposed therein for the target substrate. A vacuum container has an opening for performing maintenance of the interior. The opening is airtightly closed by a lid, which is operable for opening/closing.
A sealing member, such as an O-ring, is interposed between the lid and vacuum container, to ensure that the container is airtight when the lid is closed. Accordingly, it is important to prevent the sealing member from being abraded or twisted, when the lid is being operated for opening/closing. U.S. Pat. No. 6,050,446 discloses a lid apparatus arranged to prevent a sealing member from being abraded or twisted.
This lid apparatus includes a lid for opening/closing an opening of a vacuum container. The lid is pivotally supported by an axial support disposed on a side of the vacuum container. The lid is provided with a support shaft extending through its center of gravity. The opposite ends of the support shaft are rotatably supported by drive cylinders disposed on sides of the container main body. The lid is operated for opening/closing while rotating about the axial support in accordance with extension and contraction of the drive cylinders. The axial support of the lid is oblong, so that the lid can be set in parallel with the opening when the lid is closed. This device however has a problem in that the drive portion takes up much space, and thus the device becomes large.